I asked the Assistant AG of California why carrying a handgun was a misdemeanor (at the time), but a sap. club, etc. was a felony. He said it dated back to when "silent means of attack" were used to Shanghi sailors in San Francisco!
Back in 19 mumble-mumble, when I started in Law Enforcement, I was issued a sap, and told "NEVER use it!". Why? Because we were always hitting each other on the backswing! It's still around here someplace - I never did even carry it.
And the difference between a cane and a sap is the difference between a lever action .44 mag rifle and an AR 15. One is "normal" that a judge or jury might have at home, the other is ""evil"".